000
AXNT20 KNHC 191809
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE FEB 19 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE 
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION 
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS... 
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1745 UTC

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N12W 0N24W 4S37W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED 90 NM OF 6N12W AND 
WITHIN 120 NM OF THE ITCZ AXIS S OF THE EQUATOR W OF 33W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH IS SWINGING E ACROSS N FLORIDA WHILE AN 
UPPER RIDGE EXTENDS NW OVER THE SE PORTION OF THE GULF. AT THE 
LOW LEVELS A BROAD FRONTAL ZONE IS ANALYZED AS A COLD FRONT FROM 
SW FLORIDA TO NEAR 23N87W WHERE IT BECOMES QUASI STATIONARY TO 
THE EASTERN BAY OF CAMPECHE. BROKEN TO LOCALLY OVERCAST LOW AND 
MID LEVELS CLOUDS...WITH EMBEDDED SHOWERS...IS WITHIN 30 NM S 
AND WITHIN 120 NM N OF THE ANALYZED FRONT. THE UPPER LEVELS AREA 
VERY DRY ELSEWHERE W OF THE FRONT. BROKEN TO OVERCAST LOW AND 
MID LEVEL CLOUDS ARE NOTED W OF 92W.
  
CARIBBEAN...
AN UPPER LEVEL RIDGE ORIGINATING OVER S AMERICA COVERS THE W 
CARIBBEAN WHILE A CENTRAL ATLC UPPER TROUGH HAS SHIFTED W OVER 
THE PORTION E OF 70W. DEBRIS MOISTURE IS SPREADING N OVER THE SW 
CARIBBEAN TURNING ENE ALONG THE RIDGE CREST ACROSS CENTRAL CUBA. 
OTHERWISE THE UPPER LEVELS ARE DRY SUPPRESSING CONVECTION TO 
ONLY LIGHT TRADE WIND SHOWERS ARE RACING W ACROSS THE REGION NE 
OF A LINE FROM GRENADA TO W CUBA.
 
ATLANTIC...
AN UPPER TROUGH IS MOVING E OFF THE SE COAST OF THE CONUS. THE 
ASSOCIATED COLD FRONT LIES ALONG 32N73W 26N80W WITH A PRE 
FRONTAL TROUGH ABOUT 150 NM AHEAD OF THE FRONT OVER THE BAHAMAS. 
BROKEN TO OVERCAST MULTILAYERED CLOUDS ACCOMPANY THE FRONT WITH 
MOSTLY EMBEDDED SHOWERS W OF THE BAHAMAS...BUT A FEW TSTMS NE OF 
THE BAHAMAS ARE CONFIRMED BY LIGHTNING DATA. AN UPPER RIDGE 
EXTENDS N FROM S AMERICA ACROSS THE SE BAHAMAS BUT THE RIDGE 
CREST HAS BECOME UNSTABLE NEAR 25N73W AND IS BEGINNING TO 
COLLAPSE SE. AN UPPER LEVEL TROUGH...TUTT...EXTENDS SW FROM A 
DEEP LAYERED SUBTROPICAL UPPER CYCLONE AT 30N37W THROUGH ANOTHER 
UPPER CYCLONE AT 17N53W TO AN ILL DEFINED CYCLONE OVER THE E 
CARIBBEAN AT 13N64W. UPPER DIFFLUENCE IS ENHANCING A FEW SHOWERS 
WITHIN 180 NM SW AND WITHIN 270 NM NE SEMICIRCLES OF THE CYCLONE 
AT 30N37W. OTHERWISE THE SW ATLC IS QUITE DRY ALOFT N OF 18N 
BETWEEN 65W AND 35W AND S OF 18N BETWEEN 70W AND 45W. THE 
ASSOCIATED SURFACE LOW AT 31N38W IS EXPECTED TO CONTINUE MOVING 
SSE TONIGHT AND EVENTUALLY DISSIPATE LATER THIS WEEK. CONVECTION 
CONTINUES FAIRLY CLOSE TO THE CENTER AND THE SYSTEM WILL BE 
CLOSELY MONITORED FOR SIGNS OF SUBTROPICAL FORMATION.  
     
AN UPPER ANTICYCLONE IS AT 5N13W WITH A RIDGE EXTENDING W TO A 
SHARP CREST AT 10N49W. A LARGE MOISTURE PLUME ORIGINATING FROM 
CONVECTION S OF THE EQUATOR IS SPREADING NE ALONG LINE 4N51W 
16N30W 18N15W. AT THE LOW LEVELS A LARGE AREA OF DUST AND 
SUBSIDENCE IS NOTED S OF 12N E OF 52W.

$$
NELSON